CODEWITHSUNDEEP
iphoneiosipad
hacker
hacker

Reputation: 8947

How to remove all the dictionaries from an NSmutablearray which contains a particular key?

I have an IPhone application in which I have an NSMutableArray of dictionaries. When selecting each row of the table, I am deleting the dictionaries by using 

if (indexPath.row <[self.newmessagearrays count])
{
     [messagearrays removeObjectAtIndex:indexPath.row];
}

I have a scenario in which I want to remove all the dictionaries in which my "from id" key is the same, when the row is tapped. I tried like this, but with no effect:

 NSPredicate * pr = [NSPredicate predicateWithFormat:@"userid == %@",fromidstring];
[messagearrays filterUsingPredicate:pr];

Upvotes: 1

Views: 232

Answers (3)

AsifHabib
AsifHabib

Reputation: 950

Array keeps objects at some index, dictionary keeps object and keys so your algorithm should be like this

Get object(dictionary) from array one by one using loop, check that your dictionary has that specific key.
if yes, remove that object from array using function removeObjectAtIndex

Upvotes: 0

justin
justin

Reputation: 104698

You can filter the array in place using NSPredicate:

NSPredicate * pr = [NSPredicate predicateWithFormat:@"containsKey == SOME_KEY"];
[messageArrays filterUsingPredicate:pr];

Update

In response to edit/clarification:

NSPredicate * pr = [NSPredicate predicateWithBlock:
  ^(id dictionary, NSDictionary * bindings) {
    return (BOOL)![[dictionary objectForKey:@"fromid"] isEqual:@"190"];
}];
[messageArrays filterUsingPredicate:pr];

Upvotes: 4

blub
blub

Reputation: 1014

NSMutableIndexSet *discardedItems = [NSMutableIndexSet indexSet];
NSDictionary *item;
NSUInteger index = 0;

for (item in yourArrayOfNSDictionaries) {
    if ([dictionary objectForKey:theKeyYouWantToCheckFor] != nil) [discardedItems addIndex:index];
    index++;
}

[originalArrayOfItems removeObjectsAtIndexes:discardedItems];

Upvotes: 0

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